Cargo very seldom fits into a vessel hold, railroad boxcar, or truck trailer or container so efficiently that no space exists between the cargo or lading and any side wall of the vessel or vehicle or between cargo. Even pellets on which presently so much cargo is mounted are found typically not made to be exactly evenly divisible into a conventional cargo load space. Also, the variance in size of individual cargo or product containers often results in what is termed as pallet underhang or overhang when the containers are palletized, thereby assuring that, in most cases, a gap, or gaps, will be present laterly or horizontally across a fully loaded cargo space. In order to prevent damage caused by goods shifting into these cargo space gaps during transit, dunnage plugs are used to fill the voids which exist between individual cargo containers, pallets, or between one side of a cargo container and a side wall of the cargo space, be it a vessel hold, railroad boxcar, truck trailer, or the like.
While dunnage plugs may be made from any light, inexpensive or waste-type material of choice, several heretofore known types of dunnage plugs have been made from laminated, corrugated cardboard and other paper products. Examples of such dunnage plugs are shown and described in U.S. Letters Patent listed above and whose disclosures are incorporated herein by reference or background data. It is known as shown by the Jaski patent, supra, that plugs can be made of sheets bent into U-shaped channels. The dunnage plugs disclosed are made from a plurality of cardboard sheets which are bent to form U-shaped channels, or channel-shaped structures, each having opposed parallel side members and a base or web extending perpendicularly between the side members along one edge of each. The plurality of channel members are arranged in parallel groupings with the groups being oriented perpendicularly to each other. The opposing parallel side members of the channels each include a plurality of parallel interior slots formed therein which extend inwardly from the outer long edges of the channels; and they are positioned such that the slots, and therefore the channel-shaped structures, may perpendicularly engage or interlock with each other in essentially half cross-lap-joints. The planes defined by the flat webs or bases of the respective channels are positioned in parallel spaced apart relation when the channels are interlocked. The interlocking groups of channels form structure which has strength against compression across the formed thickness of the plug. It should be noted that the corrugations in the cardboard are positioned, when the channels are folded, to run parallel across the gap to be filled. It is known that while corrugated cardboard does have some strength against a compressive force positioned perpendicular to the laminated joints therein, it has a much greater resistance against compression from a force directed parallel to the laminations or corrugations.
The multi-piece dunnage plugs, especially those plugs where the various pieces differ in size, have disadvantages in that some of the pieces may become lost on the loading docks, freight yards, or the like where these items are used or if one piece damaged entire unit is useless. Additionally, if the dunnage plugs are attached, such as by stapling, to the interior sides of a vehicle or vessel, the channels perpendicular to those having staples therein may separate from the stapled channel. For example, if the non-stapled channels happen to be struck on their side surfaces, or on end, by cargo as it is being loaded adjacent to a wall mounted dunnage plug. Free-standing dunnage plugs may be subject to moisture damage from flooring, collapsing and the like.
It is therefore an object, feature, and advantage of the present invention, generally stated, to provide a blank for a new and improved one-piece or unitary dunnage plug.
Another object and advantage of the present invention, generally stated, is the provision of an improved dunnage plug constructed from a single sheet of material, preferably laminated, corrugated cardboard, which may be assembled, disassembled and stored, either for initial use or reuse, as a single sheet.
It is a further object of the present invention to provide an improved one-piece blank for a dunnage plug which includes a plurality of intersecting, interfitting, interlocking U-shape channel structures wherein the planes defined by the webs or bases of the respective channels perpendicularly intersect.